Choosing a Walking Rucksack: Size and Fit | Footpath Notes
Choosing a walking rucksack is easier when you start with the kind of days you actually walk, rather than a long list of features. This practical guide covers the decisions that shape a useful day pack: capacity, a stable fit, weather protection, accessible storage and a sensible way to carry essentials. Footpath Notes is an independent British guide to walking and hiking in the UK, with advice focused on conditions across local paths and longer routes. Use the guidance to compare packs and assess comfort under load, not just appearance. A well-chosen pack should carry what your route needs without making the walk feel cumbersome.
Choosing the size
A walking rucksack’s capacity is usually stated in litres, but the number is a guide to how much it can hold rather than a guarantee of usable space. Choose a size around the demands of your usual walk: a short outing needs less room than a full day on exposed hills or an overnight trip. The ranges below are practical planning bands, not a formal industry classification. Compare how each maker measures capacity before treating two packs with the same litre figure as equivalent.
Litres explained
Litres describe the volume a rucksack can hold. A 25-litre pack is intended to provide about 25 litres of capacity, but the figure does not tell you the exact shape of the main compartment or how easily your own items will fit inside it. A tall, narrow pack and a shorter, wider one can have the same stated capacity yet feel quite different to use.
There is no single measuring standard followed by every rucksack maker. Brands may differ in how they calculate the main compartment, lid, pockets or expandable sections, so published capacities are not always directly comparable. One maker might include more secondary storage in its total than another, while a roll-top design may have a variable volume depending on how it is closed.
When comparing two packs, check what the stated capacity includes and look for a clear breakdown of the compartments. If that information is not available, compare the shape and dimensions as well as the litre figure, or try both packs with the items you normally carry. This makes the walking rucksack size guide more useful than relying on a number alone: capacity is a helpful starting point, but it is not a universal measure of how much practical space a pack offers.
Day walks and longer trips
Choose capacity according to the duration and demands of the walk, as well as the amount of food, spare clothing and other personal essentials you carry. These ranges are practical sizing guidance rather than a formal standard; a full day on British hills commonly calls for a 25–30-litre pack.
| Capacity | Typical use | What it can accommodate |
|---|---|---|
| 10–20 L | Short walks | Water, food, a light spare layer and a few small essentials. |
| 20–35 L | Full days on hills | Food, water, extra clothing and the additional items needed for a longer day outdoors. |
| 40 L or more | Overnight trips | Day-walking essentials plus overnight clothing, a sleeping bag and other sleep-system or camp items, depending on their size. |
A 10–20-litre pack suits a short outing when your load is limited; bulky spare layers may push you towards the upper end. For a full day on the hills, 20–35 litres allows more room for changing conditions and extra provisions, with 25–30 litres a common middle ground on British hills. A capacity of 40 litres or more is generally needed when you must carry overnight equipment, though the exact size depends on how compact that equipment is and whether you share group gear. If your walks vary, choose for the trip you do most often rather than carrying a much larger pack on every short walk.
Fit and features
A comfortable pack depends on a harness that matches your back, stays stable as you walk and lets you reach essential items without stopping. Torso length is more useful than height when choosing the pack size. Belts, straps and back panels affect how the load feels, while rain protection helps keep the contents dry. Check these details with the pack adjusted and, where possible, carrying a typical walking load.
Back length and hip belt
The key measure for fit is torso length, not your overall height: people of the same height can have different back lengths. Learning how to fit a walking rucksack starts with measuring from the prominent C7 vertebra at the base of the neck to the top of the hip bones.
- Tip your head forward to locate C7, the prominent vertebra at the base of your neck; stand naturally rather than stretching your back.
- Place your hands on your hips with thumbs pointing towards your spine; the line between your thumbs marks the top of the hip bones.
- Ask someone to measure from C7 down the curve of your back to that line, keeping the tape close without pulling it tight.
- Use the measurement to compare pack sizing charts, since a small, medium or large harness can correspond to different torso lengths between makers.
- Position the hip belt so its padded centre sits over the hip bones; fasten it snugly, then tighten the shoulder straps without lifting the belt.
- The hip belt carries part of the pack’s weight on your hips, reducing the load borne by your shoulders when the pack is properly adjusted.
- Many day rucksacks under about 20 litres have no hip belt; a sternum strap can still connect the shoulder straps and limit sideways movement.
Ventilated back panels use shaped mesh or channels to leave space for airflow, although the design varies and does not eliminate perspiration. If you use a hydration reservoir, check for an internal sleeve and a hose exit that lets the tube sit securely over a shoulder strap.
Rain covers and pockets
Rain protection matters because wet contents can make clothing and spare layers uncomfortable to use on a walk. A fitted cover and an internal dry-bag liner work differently, and pockets determine how quickly you can reach small essentials.
- A rain cover sheds water from the outside of the pack and can be removed when the weather clears; choose one that matches the pack’s shape.
- In strong wind, a cover can catch the air and blow off, so check its elastic edge and any attachment points before setting out.
- A dry-bag liner sits inside the main compartment and protects contents even if water passes the outer fabric or the cover shifts in gusts.
- Using both gives separate layers of protection: the cover reduces wetting on the pack exterior, while the liner keeps packed items enclosed.
- Top pockets suit small items needed during a walk, while side pockets can keep a drink bottle reachable without opening the main compartment.
- Hip-belt pockets keep compact essentials close at hand; check that they open easily and do not press uncomfortably against your body.
- A hydration-compatible pack should provide a reservoir sleeve and a route for the hose, so you can drink without unpacking or searching a pocket.
For exposed or changeable weather, an internal liner is a dependable way to keep the main contents contained if a cover is displaced. Use pockets for items you expect to reach often, rather than relying on the main compartment for every small essential.
Packing a day rucksack
A useful day pack carries the essentials without burying them beneath spare clothing or food. Group similar items so you can find what you need while standing on a track or taking a short break. Keep the load stable as the route changes from open path to steep ground, and protect clothing that needs to stay dry. The contents below cover changing weather, navigation, comfort and basic emergencies.
What goes in
Choose contents for the route, forecast and time you expect to be out, then keep small essentials together so they do not disappear among clothing. These hill-walking basics cover changing conditions and common needs on a day walk.
- Carry 1–2 litres of water for a typical day walk, adjusting the amount for heat, exertion and reliable refill points along your route.
- Pack food that is easy to eat during a break, such as sandwiches or snacks in a sealed container, and keep wrappers for carrying home.
- Take a waterproof jacket and over-trousers, even when the walk starts dry; pack them where they can be reached quickly if rain arrives.
- Bring a spare insulating layer, plus a hat and gloves, to add warmth when you stop or conditions become colder on exposed ground.
- Carry a map covering the route and a compass, and know how to use both; keep them protected from rain but readily accessible.
- Pack a head torch with its batteries, rather than relying on a phone light, so you have hands-free illumination if the walk takes longer.
- Include a compact first-aid kit, an emergency shelter and a whistle, keeping these essentials together so they can be found without unpacking everything.
Use a waterproof liner or dry bag to protect spare clothing and other contents from rain inside the pack. Check the forecast and route before setting out, then remove items that do not suit the planned walk.
How to load it
Pack to keep the rucksack steady against your back and to make useful items accessible without unloading it. A simple order from the centre outwards helps prevent the contents shifting on uneven paths.
- Place the heaviest items close to your back and around mid-height; this keeps the load close to your centre rather than pulling backwards.
- Pack weight evenly from side to side, and secure loose contents so they cannot swing when you step over rocks or climb a slope.
- Put items needed often near the top or in pockets, leaving enough room to reach them without removing clothing or repacking the main compartment.
- Keep waterproof layers near the top or in an accessible pocket, so you can get to them promptly when rain begins.
- Arrange spare layers around the heavier contents to fill gaps and limit movement, while avoiding pressure that makes the pack uncomfortable against your back.
- Store emergency equipment where it remains reachable if conditions change; do not bury it beneath food, spare clothing or other less urgent contents.
Before leaving, lift the packed rucksack and walk a few steps to check that nothing shifts or presses uncomfortably. Reposition any loose or awkward contents before starting the route.